class_docstr: Widget for proportionally dividing its internal area into a grid.
  
  This widget will automatically set the position and size of child widgets
  according to provided constraints.
  
  Parameters
  ----------
  spacing : int
      Spacing between widgets.
  **kwargs : dict
      Keyword arguments to pass to `Widget`.
code: def grid_size(self):
      rvals = [
          widget[0] + widget[2]
          for widget in self._grid_widgets.values()
      ]
      cvals = [
          widget[1] + widget[3]
          for widget in self._grid_widgets.values()
      ]
      return max(rvals + [0]), max(cvals + [0])
  
imports: from __future__ import division
  import numpy
  from vispy.geometry import Rect
  from .widget import Widget
  from .viewbox import ViewBox
  from kiwisolver import Solver, Variable, UnsatisfiableConstraint
label_desc: Use image node_id 10 for calling the Grid obj's underlying member method code with example usage: obj.grid_size() and returns: max,  max